Human response and public opinion on Ping river floods

This webpage is a short description of the human response during floods, before and after and the public general opinion about floods. Further information and references can be found in 'Floods and Water Management in Chiang Mai and the Upper Ping Catchment (Pirard, 2025)'.

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FAQ

Communities have lived for centuries with seasonal floods during the wet monsoon and have adapted their lifestyle, architecture, settlements, traditions and beliefs to it. However, in the last few decades, a growing perception that floods are a hazard that need to be controlled has emerged with a public opinion trending towards a feeling that floods increased in magnitude and frequency due to climate change, deforestation, mismanagement, urbanization and population growth.

In the last couple of decades, flooding has become a significant hazard in the Upper Ping river causing extensive economic losses due to inundated farmland, reduction of commercial activities and residential damage. Direct loss from flooding covers areas in contact with floodwaters such as buildings, harvests, farm animals, cars and transportation, but also costs in lives and injuries, harm to cultural sites and biological destruction. Indirect losses and costs are due to temporary halt of income for businesses and trade, industrial disruption, ecological loss, transportation disruption, legal costs in lawsuits, stress and anxiety, loss of community and ecological resources, etc.

Pre-flood behaviour

The first warnings of a risk of floods can be produced as early as 48 hours before it occurs in Chiang Mai due to the time it takes for rains to come down from the headwaters. However, it’s only 6 to 7 hours before a flood, that measurement in station P.67 can be accurately translated into water levels in the inner city of Chiang Mai (station P.1). This warning system has been in place for 3 decades and only have minimal errors on the forecast. Combined with flood-risk maps of downtown Chiang Mai, anticipation of the flood is now the norm. It wasn’t always the case, such as the first major flood of 2005 when warnings were ignored by the population due to the lack of education relative to floods, the absence of major floods for more than a decade and the assumption that the government project of river expansion, dredging and flood protection was adequate. When the 2005 mid-August flood hit Chiang Mai, the population was unpreprared, leading to extensive damage and unfortunately several fatalities.

Figure 1. Arrival time to P.1. of flood waters between river level measuring stations in the upper Ping

Fortunately, the followings floods in 2005 met a more prepared population. Floods in 2011, 2022 and 2024 did not meet the level of unprepareness seen in 2005 although some specific conditions, combined with inadequate resources and poor coordination can remain an issue. Some inherent difficulties remain in decision-making by the local government and the population. In the past decade, a major change has been brought by social media which has considerably easened access to information with many updates available on the ground situation, real-time flood conditions, help available, etc. Unfortunately, social media is also now used to spread significant misinformation (or possibly disinformation) on various type of ineffective flood protections and a focused attention on the inability of local authorities to manage the situation. It is not different from social media in normal time but in case of emergencies, it has the result of wasting valuable time in the pre- and syn-flood preparation and community help. Another parasitic trend on social media is the fascination for extraordinary, excessive and anxiogenic false claims widely distributed by users and information channels.

Figure 2. Example of a fake model of flooding at +5.5 m in P.1. widely shared on social media during the pre-peak period of the 2024 floods under an argument of authority. The image here is made by an non-specialist academic in search of publicity during a disaster and basically represents the water level in Chiang Mai if the sea level rise by 311 meters. There is no science or realism in this, just an idiotic map. Realistic flood modeling is the subject of serious scientific publications and advanced computing (see trends and modeling)

Flood perception, preparation and effects

Rural residents generally face recurrent floods and are traditionally used to it. They are overall more prepared than their urban counterpart with more adaptive strategies and a lot more autonomous. Urban population relies on flood protection measures and government actions such as the distribution of sand bags or concrete blocks and are less flexible when dealing with rising waters.

The amount of damage (as sum of property damage, agricultural output, health loss, forgone income, etc.) is obviously directly dependent on the level and duration of flooding occurring in an area. Despite preparation in minimizing damage, complete prevention is generally not possible without significant investment and some predetermined factors are known to have an influence on the damaged incurred during a flood.

- Prior experience and awareness of vulnerability is a very important factor, that can in theory be enhanced through disaster training and preparedness but such educative programs are mostly inadequate in Thailand.

- Adaptive behaviour is important when managing time available since initial warning, while waters are rising, selective decisions on minimizing damage and evacuation decisions. Interestingly, collective adaptation through social organization with the building of flood protections in public areas seemed to have no effect in the damage occurred within the area.

- Acquisition, understanding and usage of all available information channels did not seem to have a significant effect two decades ago but the situation changes significantly from one flood to another. The dynamic nature of social media regarding information probably has a positive effect.

- A fatalist attitude or perception of future severity lead generally to more losses than victims that kept trying to do something about it.

- Level of income has a proportional effect. Higher income, partly correlated with higher education has a relative damage significantly less (9.4% of monthly income) than poorer social classes (54.2% of monthly income). However, in absolute financial loss, higher income, also correlated with middle age and mildly old households, occurred more damage than houses occupied by young people, elderly and poor people that have less possessions.

Post-Flood surveys

Health issues show that 20% of the population suffer from skin infection, fungal feet infection as well as some chronic dizziness and diarrhea. Post-flood dried mud in busy streets is mobilized by traffic and can create a significant amount of dust that can be an issue for sensitive individuals.

Post-flood recovery varies from a few hours to days or weeks in rural and poorer areas. Recovery signifies a return to usual conditions for the population. It includes access to drinking water, running water, electricity, food, labour, etc.

Post-flood surveys show in 2005 that 75% of respondents would pay more attention to weather updates and warning to know when floods are coming. This proportion has likely significantly decreased 2 decades later. 40% of the rural population also would consider harvesting food earlier if the flood warning allowed it but on that aspect, little has changed since 2005.

Post-flood changes to the household to implement significant and permanent flood protection such as building an upper floor or raise the surrounding grounds is considered but financial constrailn is the main limitation.

Water damage insurance covers are considered by 40 to 60% of residents but the clear definition of high floor risk areas in the Chiang Mai basin, with the recent history of flooding makes it difficult.

Temporary work is not sought by the urban population when their normal occupation is not possible. In rural areas however, there is some interest in this idea (12%), possibly due to flooding lasting sometimes several weeks in farmlands.

Following the 2005 floods, one third of urban residents considered to relocate while only 4% are interested by this option in rural areas. While the new flood protections made prior to 2005 failed to protect the city, 23% of urban residents at the time thought that flood would be less severe in the future due to additional projects for the waterways, while 28.5% thought it will be more severe. 25% of rural residents also stated that they would not change anything to their household as they would expect the government to find solutions before the next flood. No data on this subject is available for recent floods but it is likely the opinion supporting increasing severity has similar percentage or higher. Two decades of various works on waterways have not changed much in the frequency and intensity of floods and promises made post-2005, post-2011, 2022 and 2024 still need to be realized. Although some projects such as the Mae Kuang Udomthara Reservoir Project could alleviate some flooding, the public might not be sufficiently informed to have a meaningful opinion on the effect of this mega-project and is possibly skeptical of such promises of flood control (see infrastructure)